Parent/child relationships may be published in geographic data files (GDFs) and are referred to as relationship feature code 1026. However, dependent upon which GDF map supplier is used, the representation may be different. For example, NAVTEQ of Chicago, Ill. publishes a point of interest (POI) database with a feature code disclosing a parent/child relationship. In the NAVTEQ database, the relationship features code between two service (POIs) with a physical relationship that carries a value of P. Services may have up to or more than 100 children. In the TELEATLAS database, multi-tenant coding is provided by their POI partner, Infogroup to support service belonging to service relationship. Tenant coding of “C” would be used for buildings with multiple tenants.
U.S. Pat. No. 6,542,817 illustrates a route search method in a navigation system in which POI (Point of Interest) information regarding POIs is incorporated in map information and a route up to a specified POI is searched for. When a POI has a plurality of gateways, identification data for road links connected respectively to the gateways is incorporated in the POI information. When a certain POI is set as the destination, the navigation system refers to the POI information and checks whether a plurality of road links are stored corresponding to the set POI. If so, the system searches for a route up to each of the road links, and determines an optimum one of the found routes as the guide route.
US Patent Application 2010/0145606 illustrates a method for representing locations in a geographic database in a manner that facilitates navigation and routing. A core map database includes data that represents public roads in a geographic region. Each of a plurality of location map databases includes data that represent facilities, such as businesses, stores, offices, or other places, that are physically located away from the public network and access to which requires travel on paths away from the public road network. Each of the facilities represented in the location map databases is assigned a location reference code that is associated with data from which a path connecting the facility and the public road network can be determined.
U.S. Pat. No. 7,603,231 illustrates a navigation system that guides a user to a destination with an improved arrival detection capability when the selected destination is a large facility or a natural place that occupies a relatively large area. When a particular destination is specified by the user, the navigation system calculates a route to the destination based on the address of the specified destination. The navigation system also checks whether the specified destination is associated with polygon data. When the specified destination is associated with the polygon data, the navigation system creates an arrival detection start range. After reaching the arrival detection start range, the navigation system detects the arrival at the destination when any part of the polygon of the destination comes within an arrival detection range of the navigation system.